In general, a small-sized camera module is mounted in a portable terminal, such as a smartphone. A lens driving device, which has an autofocus function to automatically perform focusing during imaging a subject (hereinafter, referred to as an “AF function”) and an optical image stabilization function (hereinafter, referred to as an “OIS function”) to optically correct shake (vibration) generated during imaging and reduce distortion of an image, is applied to such a camera module (for example, PTL 1 and PTL 2).
The lens driving device having an autofocus function and an optical image stabilization function includes an auto-focusing driving part (hereinafter, referred to as an “AF driving part”) that moves a lens part in an optical-axis direction and an optical image stabilization driving part (hereinafter, referred to as an “OIS driving part”) that allows the lens part to sway in a plane orthogonal to the optical-axis direction. In PTL 1 and PTL 2, a voice coil motor (VCM) is applied to the AF driving part and the OIS driving part.
An AF driving part employing a VCM driving system includes, for example, an auto-focusing coil (hereinafter, referred to as an “AF coil”) that is disposed around a lens part and an auto-focusing magnets (hereinafter, referred to as “AF magnets”) that are disposed so as to spaced apart from the AF coil in a radial direction. An autofocus movable part (hereinafter, referred to as an “AF movable part”) including the lens part and the AF coil is supported by an autofocus support part (hereinafter, referred to as an “AF support part”, for example, a leaf spring) in a state where the autofocus movable part is spaced apart from an autofocus fixing part (hereinafter, referred to as an “AF fixing part”) including the AF magnets in a radial direction. The AF movable part is moved in the optical-axis direction by the driving force of a voice coil motor including the AF coil and the AF magnets, so that focusing is automatically performed. Here, the “radial direction” is a direction orthogonal to the optical axis.
The OIS driving part employing a VCM driving system includes, for example, optical image stabilization magnets (hereinafter, referred to as “OIS magnets”) that are disposed in the AF driving part and optical image stabilization coils (hereinafter, referred to as “OIS coils”) that are arranged so as to be spaced apart from the OIS magnets in the optical-axis direction. An optical image stabilization movable part (hereinafter, referred to as an “OIS movable part”) including the AF driving part and the OIS magnets is supported by an optical image stabilization support part (hereinafter, referred to as an “OIS support part”, for example, suspension wires) in a state where the optical image stabilization movable part is spaced apart from an optical image stabilization fixing part (hereinafter, referred to as an “OIS fixing part”) including the OIS coils in the optical-axis direction. The OIS movable part is allowed to sway in a plane orthogonal to the optical-axis direction by the driving force of a voice coil motor including the OIS magnets and the OIS coils, so that optical image stabilization is performed.